SOLUTION: A bag is filled with 16 red marbles and 49 white marbles. With replacement what is the probability of picking a red mable. I do not understand how to use replacemnet to find the a

Question 334673: A bag is filled with 16 red marbles and 49 white marbles. With replacement what is the probability of picking a red mable. I do not understand how to use replacemnet to find the answer. Thank you.
Found 2 solutions by solver91311, stanbon:
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!

Replacement doesn't make any sense in the context of the probability of picking a red marble. Now if you were interested in the probability of picking a red marble on the second (or subsequent) trial, THEN replacement makes a difference.

If you are only concerned with the first try, replacement doesn't matter. The probability is simply the number of red marbles divided by the total number of marbles.

But if you want the probability of picking a red one on the second try, you have to consider whether the one you picked in the first place 1. was red or not, and 2. went back in the bag.

Here's the deal. The probability of picking a red marble on the first go is . Now if you put the marble back in the bag, the probability of picking a red one on the second go is exactly the same, because you have the same total number of marbles and the same number of red marbles. BUT, if you DON'T put the first one chosen back in the bag, then things change.

In this case, if the first marble chosen was white, then you would have 16 red marbles and 48 white marbles left in the bag for the second draw and the probability would be . But if the first one was red, then the probability of picking a second red one is now

See?

John

My calculator said it, I believe it, that settles it

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A bag is filled with 16 red marbles and 49 white marbles. With replacement what is the probability of picking a red mable. I do not understand how to use replacemnet to find the answer.
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There is no replacement when you only make one selection.
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P(red) = 16/65
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Cheers,
Stan H.
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